1. Technical Field
The present invention relates to a virtual image display apparatus that presents a viewer with video images formed by an image display apparatus (video device).
2. Related Art
There are a variety of proposed optical systems incorporated in a virtual image display apparatus, such as a head mounted display (hereinafter also referred to as HMD) mounted on a viewer's head (see JP-A-2015-72438, for example).
As a virtual image display apparatus of this type, there is a known apparatus that achieves reduction in the size of the apparatus with high precision maintained, for example, by using, as an optical system, a light guide member that has at least two nonaxisymmetric curved surfaces that guide video image light and forms an intermediate image inside (see JP-A-2015-72438).
In the field of an HMD and other similar apparatus, it is required to achieve further size reduction with optical precision maintained, and it is desirable that a light guide member and a projection system that form the optical system of the HMD or any other similar apparatus are so configured that the length of the light guide member in the light guide direction and the overall length of the projection system are further shortened. However, the total reflection condition for guiding video image light in the light guide member, suppression of aberrations, a satisfactory angle of view, a satisfactory eye ring diameter, and a variety of other design conditions restrict the reduction in the size of the optical system, for example, by using the configuration described in JP-A-2015-72438.